Lawn anthracnose: how to fight it?

Have you noticed yellow or brownish spots spreading across your lawn, or areas that seem to be thinning out faster than usual? It is possible that your lawn is affected by turf anthracnose ( Colletotrichum graminicola) , a fungal disease that attacks lawns weakened by stress and changes in weather conditions. Let’s take a closer look at the causes, symptoms, and solutions to effectively combat this dreaded fungus.

And if you need support to improve your lawns and combat lawn anthracnose, do not hesitate to contact us . We have developed protocols and natural solutions that allow you to control and combat this lawn disease.

Description of anthracnose in lawns

Anthracnose of turf is caused by the fungus Colletotrichum graminicola . This fungal disease primarily targets lawns that are weakened, mainly due to high temperatures, drought or nutritional deficiencies. 

Present mainly during the summer months, from June to August , anthracnose can also emerge in the spring, from May, and extend its activity until the fall in September and October. 

This fungus develops on the surface, on the leaves and stems , and causes lesions that quickly compromise the quality of the lawn, degrading lawns in gardens as well as those on sports fields. The infection first appears as spots which, if left untreated, spread and eventually strip the lawn bare, leaving dry and unsightly areas.

Which plants are susceptible to turf anthracnose?

Some turfgrass species are particularly susceptible to anthracnose, such as annual bluegrass ( Poa annua ), bentgrass ( Agrostis spp. ), and red fescue ( Festuca rubra ). These varieties, commonly used in gardens and golf courses, show a greater susceptibility to this fungal infection, especially if they are subjected to stressful conditions. 

Conditions favorable to the development of turf anthracnose

Anthracnose thrives under certain specific conditions. This fungus thrives particularly well when temperatures range from 25 to 30 degrees , combined with high humidity and prolonged wet foliage. 

These circumstances are exacerbated by compacted soils , where water stagnates and roots lack aeration , creating an environment conducive to the development of the fungus. 

Additionally, improper mowing practices, including mowing too low , add additional stress to the lawn. 

Nitrogen deficiencies also weaken turf, making it more susceptible to developing anthracnose, while excessive or late irrigation leaves turf wet overnight, encouraging the fungus to grow.

What are the symptoms of lawn anthracnose?

Anthracnose of lawns manifests itself by damage that affects both the visual appearance and the general health of the lawn. Here are the main symptoms that can be observed:

• Irregular spots : Yellow to brown areas appear, often arranged in bands that gradually spread.
• Thinning : the lawn begins to lose its density, we observe sparse and weakened areas.
• Black growths on stems : Infected stems show dark growths and black spots, which are the fruiting bodies of the fungus that causes the disease.
• Leaf Shedding : Affected leaves easily shed due to root rot, leaving the roots in the soil, further weakening the lawn.

These symptoms particularly affect lawns on sports fields, stadiums or golf courses, surfaces where fungal diseases such as anthracnose are a constant challenge to preserve the quality of the turf.

What preventive measures and methods are there to combat lawn anthracnose?

There are several practices that can be used to ensure proactive and sustainable management of lawns, to keep them healthy and more resistant to diseases such as anthracnose.

• Balanced nutrition : a regular and appropriate supply of nitrogen (N), phosphorus (P) and potassium (K) strengthens the health of the lawn. Deficiencies, particularly in nitrogen, make the lawn more vulnerable to fungal infections such as anthracnose. The application of YAKADOP biostimulant helps to strengthen the resistance of lawns in addition to fertilizers 
• Mowing management : Maintaining a cutting height of at least 5 cm helps reduce stress on plants. It is also recommended to avoid mowing when the lawn is wet, which limits the spread of fungal spores.
• Proper irrigation : to avoid excess moisture, it is advisable to water the lawn at the beginning of the day. This allows the lawn to dry before nightfall, thus limiting the risk of fungal infection.
• Dethatching : by removing the layer of thatch on the surface of the soil, excessive humidity is reduced which can promote the spread of disease. SILIBOOST or SILIPELLET are the main allies for this lawn dethatching operation.
• Dew Removal : On golf courses or very sensitive surfaces, removing morning dew can be a useful practice to reduce the humid conditions that favor the fungus. SILIBOOST or SILLIPELLET allows for better soil aeration, thus eliminating excessive moisture on lawns.
• Cooling during hot weather : in cases of intense heat, the application of YAKALOR helps to reduce thermal stress on the lawn.

Agrobiotop solutions against lawn anthracnose

For soil improvement (aeration and dethatching)

Biostimulants